NUMERICAL SIMULATION OF THE PACKING FRACTION OF GRANULAR PARTICULATES FORMED BY LINEAR VERTICAL DISPLACEMENT

Student: Oleksandr Dybenko

Advisor: Dr. Anthony Rosato

Abstract

There are two limiting forms of particle packing structures, i.e.,  random and ordered.  The transition from random to an ordered configuration and vice versa under the influence of different perturbations (e.g. shear and vibration) is a topic of extensive experimental, simulation and theoretical investigations by many scientific groups worldwide. Recent experimental data as well as numerical simulations results have identified some phenomenological patterns in the evolution of the bulk solids fraction of the packing.

Despite the progress that has been made, the basic mechanism through which a packing’s density increases through the application of vibrations is still far from being clearly understood. In this talk, a study on the formation of packings of spherical particles via a Monte Carlo method will be presented. Vibrations of a packing are simulated by applying a linear vertical displacement to the particles, the amplitude of which is controlled by a ‘lift factor’. The system is then allowed to relax to a stable configuration after the lift via the standard Metropolis method. This process is repeated many times until the system attains a final equilibrium density. Results to date show a distinct pattern of the solids fraction ‘evolution’ as a function of lifting parameter.